Heretofore, connecting eyes have been formed on leaf springs by separately forming the eyes at each end of the spring blank. This required the heating of one end of the blank and forming the eye by a series of forming and rolling dies and then heating the opposite end of the blank and forming the opposite end of the blank in a similar manner. The entire blank must then be heated to an annealing temperature and then quenched, requiring three die stations and sets of tooling with the transfer of the blank into each die station, as well as three separate heating operations.
In the spring forming operation of the present invention, the spring blank is heated to a working temperature and then clamped adjacent its opposite ends and the eyes are formed at each end of the blank in a series of forming operations, resulting in the forming of the eyes to size in a cycle of substantially five seconds, as the blank is passed through the machine.
This, except for the quenching and punching after the eyes are formed, is attained at one station by clamping the heated blank adjacent its opposite ends with the portions of the blank to form the eyes projecting beyond clamping anvils. Gooseneck-shaped forming dies are then moved beneath the projecting end portions of the blank and the ends are knocked down about the goosenecks by hydraulic knock-downs. Scarfing knives projecting from scrolls cut the extreme end portions of the blank to conform to the undersides of the goosenecks. The goosenecks are then withdrawn while the scrolls advance to partially form the blank ends. Sizing pins are then moved into the partially formed ends of the blank and the scrolls advance to conform the blank to the sizing pins and back finishing dies of the clamping anvils. The eye pins are then withdrawn as are the scrolls. The clamps then release the formed blank which then is passed from the machine and punched and quenched. All of the operations are performed by hydraulic cylinders and pistons controlled by solenoid valves and operated in such a sequence as to consecutively form the blank with no interruptions.
The advantage of the invention is that the eyes may be formed to size at each end of a spring blank in a series of cyclic forming operations at a single station.
Another advantage of the invention is that the forming operation, including the operation of clamping the blank in position, may be operated by hydraulic devices under the control of solenoid operated valves operated in preselected sequences.
A still further advantage of the invention is that eyes may be formed simultaneously at both ends of the blank or may be formed separately at one end or the other of the blank, where the blank is such a blank as requires only a single eye.
A still further advantage of the invention is that the forming operation requires only one heating operation, both for forming and quenching the blank.
Another advantage of the invention is that the apparatus is designed for automation and the blank can be passed completely through the machine and eyes may be formed to size at each end of the blank in cycles of substantially five seconds for each spring blank.
Other objects, features and advantages of the invention will be readily apparent from the following description of a preferred embodiment thereof, taken in conjunction with the accompanying drawings, although variations and modifications may be effected without departing from the spirit and scope of the novel concepts of the disclosure.